City of Ottawa workers have been treating the grounds at some playgrounds to deter sand wasps from settling in.
A researcher at Agriculture and AgriFood Canada said there are more wasps than usual this year because of the weather.
"We've had lots of heat. We've had lots of rain," said Jeff Skevington. "And as a result lots of insects."
Skevington said sand wasps prefer playgrounds because dry sand is good for nesting and there's grass nearby to catch prey.
The City of Ottawa has received nearly 80 wasp-related calls this year, but Skevington said sand wasps are not aggressive.
"Unless we physically go out of our way to manhandle them they're not going to sting us," he said.